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- Title
干旱胁迫对马缨杜鹃生长和光合生理特征的影响.
- Authors
曾 松; 欧 静; 田 奥; 李苇洁; 林世成; 王洪飞; 周玉梅
- Abstract
[Objective] The changes in growth indicators and photosynthetic characteristics of Rhododendron delavayi under drought stress were explored, which provided a basis for developing and utilizing of R. delavayi resources and breeding of new drought resistant varieties. [Method] Using 2-year-old R. delavayi seedlings as the research object, the pot-controlled water method, one-way ANOV A and regression analysis were combined to study the effects of different soil moisture contents [ 80% - 100% (CK), 60% - 80% (FC60 ), 40% - 60% (FC40 ), 30% -40% (FC30 ), 20% -30% (FC20 ), 10% -20% (FC10 ) ]on the plant height, ground diameter, leaf growth indicators (such as bud length, number of new leaves, single leaf area, relative leaf water content) and photosynthetic indicators (such as chlorophyll a, chlorophyll b, and net photosynthetic rate) of R. delavayi seedlings, and to determine key soil water content thresholds for different indicators, thereby revealing their drought resistance and adaptation mechanisms. [Result] Under drought stress, the relative growth of plant height was 25. 68% -49. 86%, and all treatments were lower than CK, showing a first decreasing, then increasing and then decreasing trend; FC60 was significantly higher than FC40, FC20 and FC10, FC40 was significantly lower than FC30, and FC10 was significantly lower than other treatments; The relative growth of ground diameter ranged from 8. 92% to 13. 03%, showing a first increasing and then decreasing trend, with FC60 being the largest, but the differences among different treatments were not significant; The regression relationship between two indicators ( plant height and ground diameter) and soil moisture content did not reach a significant level. The growth indicators of leaves were as follows: bud length 0. 63 - 4. 60 cm, number of new leaves 8. 82 - 21. 86, number of fallen leaves 2. 00 - 4. 36, total number of leaves 21. 36 -34. 36, and single leaf area 25. 33 -70. 42 cm². As drought stress intensified, both bud length and number of new leaves showed a first increasing and then decreasing trend, and FC60 was significantly higher than FC30, FC20 and FC10; The number of fallen leaves showed a first increasing, then decreasing, and then increasing trend, with FC20 and FC10 significantly greater than CK; The total number of leaves showed a first increasing and then decreasing trend, with FC60 significantly higher than FC10; The single leaf area showed a decreasing trend, with CK significantly higher than other treatments, FC60 significantly higher than other treatments except for FC40, FC40 significantly higher than FC20 and FC10; Except for the relative moisture content of leaves, all other growth indicators had a significant regression relationship with soil moisture content; The optimal soil moisture content for bud length and new leaf rate was 25. 97% and 25. 18%, respectively. The soil drought buffer thresholds were 16. 30% -32. 78% and 15. 08% - 32. 78%, respectively. Under different drought stresses, chlorophyll a, chlorophyll band transpiration rate were 0. 99 -2.15 mg/g, 0.12-0.14 mg/g and 0. 46 -1. 51 mmoV(m² • s), with significant differences; There was a significant fitting relationship between stomata! conductance [0. 01 -0. 03 mmoV(m² • s)], transpiration rate and soil moisture content. The optimal soil moisture content for transpiration rate was 30. 09%, and the soil drought buffer threshold was 27. 40% -32. 78%. [Conclusion]ln an environment where drought continued to increase, R. delavayi mainly adapted to stress by changing leaf morphological indicators and transpiration rate.
- Subjects
RHODODENDRONS; DROUGHTS
- Publication
Southwest China Journal of Agricultural Sciences, 2023, Vol 36, Issue 12, p2670
- ISSN
1001-4829
- Publication type
Article
- DOI
10.16213/j.cnki.scjas.2023.12.011